/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package edu.ucla.cs.CalorieCounter;


import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
import java.lang.reflect.*;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

/**
 * This class does all the work for setting up and managing Bluetooth
 * connections with other devices. It has a thread that listens for
 * incoming connections, a thread for connecting with a device, and a
 * thread for performing data transmissions when connected.
 */
public class HeartMonitorService {
    // Debugging
    private static final String TAG = "HeartMonitorService";
    private static final boolean D = true;

    // Name for the SDP record when creating server socket
    private static final String NAME = "HeartMonitor";

    // Unique UUID for this application
    private static final UUID MY_UUID = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");

    // Member fields
    private final BluetoothAdapter mAdapter;
    private final Handler mHandler;
    private AcceptThread mAcceptThread;
    private ConnectThread mConnectThread;
    private ConnectedThread mConnectedThread;
    private int mState;

    // Constants that indicate the current connection state
    public static final int STATE_NONE = 0;       // we're doing nothing
    public static final int STATE_LISTEN = 1;     // now listening for incoming connections
    public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
    public static final int STATE_CONNECTED = 3;  // now connected to a remote device

    // Message types sent to/from via the Handler
    public static final int MESSAGE_STATE_CHANGE = 1;
    public static final int MESSAGE_READ = 2;
    public static final int MESSAGE_WRITE = 3;
    public static final int MESSAGE_DEVICE_NAME = 4;
    public static final int MESSAGE_TOAST = 5;
    
    /**
     * Constructor. Prepares a new HeartMonitor session.
     * @param context  The UI Activity Context
     * @param handler  A Handler to send messages back to the UI Activity
     */
    public HeartMonitorService(Context context, Handler handler)
    {
        mAdapter = BluetoothAdapter.getDefaultAdapter();
        mState = STATE_NONE;
        mHandler = handler;
    }

    /**
     * Set the current state of the chat connection
     * @param state  An integer defining the current connection state
     */
    private synchronized void setState(int state)
    {
        if (D)
        	Log.d(TAG, "setState() " + mState + " -> " + state);
        
        mState = state;

        // Give the new state to the Handler so the UI Activity can update
        mHandler.obtainMessage(HeartMonitor.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
    }

    /**
     * Return the current connection state. */
    public synchronized int getState()
    {
        return mState;
    }

    /**
     * Start the monitor service. Specifically start AcceptThread to begin a
     * session in listening (server) mode. Called by the Activity onResume() */
    public synchronized void start()
    {
        if (D)
        	Log.d(TAG, "start");

        // Cancel any thread attempting to make a connection
        if (mConnectThread != null)
        {
        	mConnectThread.cancel();
        	mConnectThread = null;
    	}

        // Cancel any thread currently running a connection
        if (mConnectedThread != null)
        {
        	mConnectedThread.cancel();
        	mConnectedThread = null;
        }

        // Start the thread to listen on a BluetoothServerSocket
        if (mAcceptThread == null)
        {
            mAcceptThread = new AcceptThread();
            mAcceptThread.start();
        }
        setState(STATE_LISTEN);
    }

    /**
     * Start the ConnectThread to initiate a connection to a remote device.
     * @param device  The BluetoothDevice to connect
     */
    public synchronized void connect(BluetoothDevice device)
    {
        if (D)
        	Log.d(TAG, "connect to: " + device);

        // Cancel any thread attempting to make a connection
        if (mState == STATE_CONNECTING)
        {
            if (mConnectThread != null)
            {
            	mConnectThread.cancel();
            	mConnectThread = null;
            }
        }

        // Cancel any thread currently running a connection
        if (mConnectedThread != null)
        {
        	mConnectedThread.cancel();
        	mConnectedThread = null;
        }

        // Start the thread to connect with the given device
        mConnectThread = new ConnectThread(device);
        mConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /**
     * Start the ConnectedThread to begin managing a Bluetooth connection
     * @param socket  The BluetoothSocket on which the connection was made
     * @param device  The BluetoothDevice that has been connected
     */
    public synchronized void connected(BluetoothSocket socket, BluetoothDevice device)
    {
        if (D)
        	Log.d(TAG, "connected");

        // Cancel the thread that completed the connection
        if (mConnectThread != null)
        {
        	mConnectThread.cancel();
        	mConnectThread = null;
        }

        // Cancel any thread currently running a connection
        if (mConnectedThread != null)
        {
        	mConnectedThread.cancel();
        	mConnectedThread = null;
        }

        // Cancel the accept thread because we only want to connect to one device
        if (mAcceptThread != null)
        {
        	mAcceptThread.cancel();
        	mAcceptThread = null;
        }

        // Start the thread to manage the connection and perform transmissions
        mConnectedThread = new ConnectedThread(socket);
        mConnectedThread.start();

        // Send the name of the connected device back to the UI Activity
        Message msg = mHandler.obtainMessage(HeartMonitor.MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(HeartMonitor.DEVICE_NAME, device.getName());
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        setState(STATE_CONNECTED);
    }

    /**
     * Stop all threads
     */
    public synchronized void stop()
    {
        if (D)
        	Log.d(TAG, "stop");
        if (mConnectThread != null)
        {
        	mConnectThread.cancel();
        	mConnectThread = null;
        }
        
        if (mConnectedThread != null)
        {
        	mConnectedThread.cancel();
        	mConnectedThread = null;
        }
        if (mAcceptThread != null)
        {
        	mAcceptThread.cancel();
        	mAcceptThread = null;
        }
        setState(STATE_NONE);
    }

    /**
     * Indicate that the connection attempt failed and notify the UI Activity.
     */
    private void connectionFailed()
    {
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = mHandler.obtainMessage(HeartMonitor.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(HeartMonitor.TOAST, "Unable to connect device");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    /**
     * Indicate that the connection was lost and notify the UI Activity.
     */
    private void connectionLost()
    {
        setState(STATE_LISTEN);

        // Send a failure message back to the Activity
        Message msg = mHandler.obtainMessage(HeartMonitor.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(HeartMonitor.TOAST, "Device connection was lost");
        msg.setData(bundle);
        mHandler.sendMessage(msg);
    }

    /**
     * This thread runs while listening for incoming connections. It behaves
     * like a server-side client. It runs until a connection is accepted
     * (or until cancelled).
     */
    private class AcceptThread extends Thread
    {
        // The local server socket
        private final BluetoothServerSocket mmServerSocket;

        public AcceptThread()
        {
            BluetoothServerSocket tmp = null;

            // Create a new listening server socket
            try
            {
                tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
            }
            catch (IOException e)
            {
                Log.e(TAG, "listen() failed", e);
            }
            mmServerSocket = tmp;
        }

        public void run()
        {
            if (D)
            	Log.d(TAG, "BEGIN mAcceptThread" + this);
            setName("AcceptThread");
            BluetoothSocket socket = null;

            // Listen to the server socket if we're not connected
            while (mState != STATE_CONNECTED)
            {
                try
                {
                    // This is a blocking call and will only return on a
                    // successful connection or an exception
                    socket = mmServerSocket.accept();
                }
                catch (IOException e)
                {
                    Log.e(TAG, "accept() failed", e);
                    break;
                }

                // If a connection was accepted
                if (socket != null)
                {
                    synchronized (HeartMonitorService.this)
                    {
                        switch (mState)
                        {
	                        case STATE_LISTEN:
	                        case STATE_CONNECTING:
	                            // Situation normal. Start the connected thread.
	                            connected(socket, socket.getRemoteDevice());
	                            break;
	                        case STATE_NONE:
	                        case STATE_CONNECTED:
	                            // Either not ready or already connected. Terminate new socket.
	                            try
	                            {
	                                socket.close();
	                            }
	                            catch (IOException e)
	                            {
	                                Log.e(TAG, "Could not close unwanted socket", e);
	                            }
	                            break;
                        }
                    }
                }
            }
            if (D)
            	Log.i(TAG, "END mAcceptThread");
        }

        public void cancel()
        {
            if (D)
            	Log.d(TAG, "cancel " + this);
            try
            {
                mmServerSocket.close();
            }
            catch (IOException e)
            {
                Log.e(TAG, "close() of server failed", e);
            }
        }
    }


    /**
     * This thread runs while attempting to make an outgoing connection
     * with a device. It runs straight through; the connection either
     * succeeds or fails.
     */
    private class ConnectThread extends Thread
    {
        private final BluetoothSocket mmSocket;
        private final BluetoothDevice mmDevice;

        public ConnectThread(BluetoothDevice device)
        {
            mmDevice = device;
            BluetoothSocket tmp = null;

            // Get a BluetoothSocket for a connection with the
            // given BluetoothDevice
            try
            {
            	Method m = mmDevice.getClass().getMethod("createRfcommSocket", new Class[] { int.class });
            	tmp = (BluetoothSocket) m.invoke(mmDevice, 1);

            }
            catch (Exception e)
            {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
            mmSocket = tmp;
        }

        public void run()
        {
            Log.i(TAG, "BEGIN mConnectThread");
            setName("ConnectThread");

            // Always cancel discovery because it will slow down a connection
            mAdapter.cancelDiscovery();

            // Make a connection to the BluetoothSocket
            try
            {
                // This is a blocking call and will only return on a
                // successful connection or an exception
                mmSocket.connect();
            }
            catch (IOException e)
            {
                connectionFailed();
                // Close the socket
                try
                {
                    mmSocket.close();
                }
                catch (IOException e2)
                {
                    Log.e(TAG, "unable to close() socket during connection failure", e2);
                }
                // Start the service over to restart listening mode
                HeartMonitorService.this.start();
                return;
            }

            // Reset the ConnectThread because we're done
            synchronized (HeartMonitorService.this)
            {
                mConnectThread = null;
            }

            // Start the connected thread
            connected(mmSocket, mmDevice);
        }

        public void cancel()
        {
            try
            {
                mmSocket.close();
            }
            catch (IOException e)
            {
                Log.e(TAG, "close() of connect socket failed", e);
            }
        }
    }

    /**
     * This thread runs during a connection with a remote device.
     * It handles all incoming and outgoing transmissions.
     */
    private class ConnectedThread extends Thread
    {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        
        public ConnectedThread(BluetoothSocket socket)
        {
            Log.d(TAG, "create ConnectedThread");
            mmSocket = socket;
            InputStream tmpIn = null;
            // Get the BluetoothSocket input and output streams
            try
            {
                tmpIn = socket.getInputStream();
                socket.getOutputStream();
            }
            catch (IOException e)
            {
                Log.e(TAG, "temp sockets not created", e);
            }

            mmInStream = tmpIn;
        }

        public void run()
        {
            Log.i(TAG, "BEGIN mConnectedThread");
            byte[] buffer = new byte[1024];
            int bytes;

            // Keep listening to the InputStream while connected
            while (true)
            {
                try
                {
                    // Read from the InputStream
                    bytes = mmInStream.read(buffer);

                    // Send the obtained bytes to the UI Activity
                    mHandler.obtainMessage(HeartMonitor.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
                }
                catch (IOException e)
                {
                    Log.e(TAG, "disconnected", e);
                    connectionLost();
                    break;
                }
            }
        }

        public void cancel()
        {
            try
            {
                mmSocket.close();
            }
            catch (IOException e)
            {
                Log.e(TAG, "close() of connect socket failed", e);
            }
        }
    }
}
